Automotive paint today often uses a coating composition that includes brightening material (such as mica or aluminum flakes) to reflect changes in buyer's tastes (the popularity of brilliant paint colors). Consequently, exterior automotive resin products such as bumpers which constitute the automobile are increasingly coated with a coating composition that contains brightening material in order to maintain an outer appearance that harmonizes with other regions of the automobile.
Meanwhile, for improving automobile safety, radar devices that measure distances and warn the driver when the automobile comes close to a nearby object may be provided at various parts of the automobile, for example, behind the radiator grille, the back panel, and the like. Such radar devices emit electromagnetic waves to objects to measure an intervening distance. However, if something (e.g. metal or the like) between the radar device and the object blocks the electromagnetic waves, the radar device can no longer perform its function. Therefore, exterior automotive resin products such as the radiator grille, which are positioned on the front surfaces of radar devices (parts that cover the radar devices), must be permeable to electromagnetic waves.
Given such requirements, an electromagnetic wave-permeable brilliant coated product as described in Patent Literature 1 has a brilliant urethane coated film that includes a mica as brightening material.
However, due to the fact that aluminum is conductive, it is considered difficult to obtain an electromagnetic wave-permeable brilliant coated resin product that has a brilliant coating film which includes aluminum flakes as brightening material.